Depression Diagnosis

Medically Reviewed by Jabeen Begum, MD on July 10, 2024
10 min read

Everyone experiences feelings of depression from time to time: it’s a fact of life. But this type of depression shouldn’t be confused with the different types of depression that are true medical conditions. These must be diagnosed by qualified health care professionals after an examination and depression screening tools. Diagnoses could include major depressive disorder, postpartum depressionor seasonal affective disorder (SAD), to name a few.

There is no one specific medical test that can tell if you have depression. Instead, doctors diagnose depression through a combination of lab tests to rule out other possible causes (such as hypothyroidism), depression screening tests, and by talking to you.

A depression diagnosis is often difficult to make because clinical depression can show up in so many different ways. For example, some clinically depressed people seem to withdraw into a state of apathy. Others may become irritable or even agitated. Eating and sleeping  patterns can be exaggerated. Clinical depression may cause someone to sleep or eat to excess, while someone else may almost eliminate those activities.

Someone's observable or behavioral symptoms of clinical depression may also look minimal despite profound inner turmoil. Depression can be an all-encompassing disorder, and it affects a person's body, feelings, thoughts, and behaviors in varying ways.


In the past, all mood disorders were lumped together. Now, doctors can diagnose the specific disorder or subtype of depression that you may have. For example, if you do have depression, your doctor must determine whether you have major depression, chronic depression including dysthymia, seasonal affective disorder (SAD), bipolar disorder, or some other type of clinical depression.

The different types of depression may seem the same at first, but there are differences in how they’re treated. So, it’s important that your doctor knows which type of depression you have. For example, if you have seasonal affective disorder (SAD), it is treated differently from major depression. Major depression can happen at any time of the year, but SAD is related to the changing seasons. Most people with SAD experience depression symptoms in the fall and winter, when there is less sunlight.

Treatment for SAD is usually only necessary during the low-sunlight times of the year, starting before the season changes.

There are lists of criteria to help your doctor diagnose specific types of depression. Here are some examples:

Minor depressive episode and major depression

For minor depressive episodes, you must have two to four of these symptoms for at least 2 weeks. For major depression, you must have a depressed mood or loss of interest or pleasure in life, plus four or more of these symptoms within a 2-week period:

  • Weight loss not related to dieting or illness
  • Weight gain
  • Insomnia or excessive daytime sleepiness (hypersomnia)
  • Excessive need to move around (agitation) or the opposite — difficulty moving around
  • Fatigue nearly every day
  • Feeling worthless or inappropriately guilty
  • Difficulty thinking or concentrating, unable to make decisions
  • Thoughts of death or suicide that keep coming back

Dysthymic disorder

It is marked by a feeling of depression for at least 2 years consistently (not having relief from symptoms for 2 months or longer), and no other type of depression diagnosis, as well as two or more of these symptoms:

  • Weight loss or gain
  • Insomnia or hypersomnia
  • Fatigue, loss of energy
  • Low self-esteem
  • Difficulty thinking, concentrating, or making decisions
  • Feelings of hopelessness

Seasonal affective disorder

The symptoms for SAD are the same as above, but they usually happen only during seasons when there is less daylight.

Perinatal depression (previously called postpartum depression)

With perinatal depression, parents may experience some of the above-listed symptoms, plus:

  • Not feeling like they’re bonding with the baby
  • Lack of interest in the baby
  • Feeling very anxious when around the baby or thinking about the baby
  • Feeling like they’re a bad parent
  • Feeling they may harm the baby or themselves

Your doctor may include standard medical tests as part of the initial physical exam. There’s no lab test that checks for depression, but tests can rule out other conditions or diseases that could cause some of the same symptoms as depression. Among them may be blood tests to check electrolytes, thyroid function, liver function, toxicology screening, and kidney function.

Blood tests can also be important if you’re taking medications to treat depression. When you take medications, they are metabolized (broken down) in either the kidney or the liver, depending on the medication. Blood tests will tell your doctor if you have any kidney or liver issues, and they can decide which medications to give you safely.

Other tests may include:

  • CT or MRI scans of the brain to rule out serious illnesses such as a brain tumor
  • Electrocardiogram (EKG) to diagnose some heart problems
  • Electroencephalogram (EEG) to record electrical activity of the brain

After discussing your mood and how it affects your life, your doctor may also ask you questions that are used specifically to screen for depression. The tools and questionnaires are just one part of the medical process of diagnosing depression. These tests can give your doctor better insight into your mood and help make a diagnosis with more certainty.

One example of a screening test is a two-part highly reliable questionnaire:

  1. During the past month, have you been bothered by feeling down, depressed, or hopeless?
  2. During the past month, have you been bothered by little interest or pleasure in doing things?

Your answer to the questions will help determine what the doctor does next. The doctor may ask you more questions to help confirm a diagnosis of depression. Or if your answers show you likely don’t have depression, your doctor will review your symptoms again to find their cause. Studies show that these two questions, especially when used with another test as part of the assessment process, are highly effective tools for detecting most cases of depression.

Your doctor may use other depression screening instruments that measure the presence and severity of depression symptoms, such as:

Patient Health Questionnaires (PHQs). The PHQ-9 has nine questions about your mood and everyday activities, such as your appetite and watching TV, to help your doctor come to a depression diagnosis. The PHQ-2 asks the first two questions of the PHQ-9. It’s not a diagnostic test, but a screening test, which can tell your doctor if you need further testing.

Beck Depression Inventory (BDI). The BDI is a 21-question, multiple-choice self-report that measures the severity of depression symptoms and feelings.

Hamilton Rating Scale for Depression (HRSD). The HRSD is also known as the Hamilton Depression Rating Scale (HDRS) or HAM-D. It’s a multiple-choice questionnaire that doctors may use to rate the severity of your depression.

Zung Self-Rating Depression Scale. This scale is a short survey that measures the level of depression, ranging from normal to severely depressed.

Center for Epidemiologic Studies-Depression Scale (CES-D). The CES-D is a self-reported scale with 20 questions designed for caregivers to measure how often they had depression symptoms. A higher score can help your doctor identify if you are at risk for clinical depression.

Geriatric Depression Scale (GDS). The GDS is another self-reported measure that is designed for older adults. The 15-question scale is a shortened version of the longer Geriatric Depression Scale-Long Form, which has 30 questions. The newer, shortened version can be completed in 5 to 7 minutes, making it easier to use.

When you take a test or inventory, you may feel uncomfortable responding honestly to questions or statements. The person who administers the test will ask about depression and mood, depression and cognition, and the physical feelings of depression such as lack of energy, sleep disturbance, and sexual problems. Be as honest as you can when assessing your symptoms. Keep in mind that the questionnaires and screening tools can’t make the diagnosis and shouldn’t be used that way. They aren’t a substitute for a clinical diagnosis made from a thorough interview. They are tools that can help a mental health professional make a diagnosis.

Feelings of depression can happen from time to time as life events affect you. Occasional depression isn’t usually a problem. It’s when the depression symptoms start to have an impact on your life that you need to get a diagnosis so you can have treatment. 

To be diagnosed with major depression, you must have a depressed mood or have lost interest or pleasure in life, plus have four of the symptoms listed above.

Depression symptoms can last weeks, months, or sometimes years. They can affect your personality and interfere with your social relationships and work habits, potentially making it difficult for others to have empathy for you. Some symptoms are so disabling that they interfere significantly with your ability to function. In very severe cases, people with depression may be unable to eat, maintain their hygiene, or even get out of bed.

Episodes may happen only once in a lifetime or may be recurrent, chronic, or longstanding. In some cases, they seem to last forever. Symptoms may start or worsen during a life crisis. At other times, they may seem to happen at random.

It’s not unusual for someone with a medical illness such as heart disease or cancer to become depressed. If you have other medical problems that could be the trigger or add to your depression, talk to your doctor about it. Being depressed can worsen the outcome for serious illnesses.

Yes, there are physical symptoms associated with depression. In fact, a great many people with depression see their doctor first with only physical issues, not realizing their problems could be related to depression. You might experience:

  • Pain, including:
    • Back pain
    • Headaches
    • Joint pain
    • Limb pain
  • Nausea
  • Abdominal pain
  • Constant tiredness (fatigue)
  • Insomnia
  • Hypersomnia
  • Slowing of physical movement and thinking
  • Changes in appetite
  • Unintended weight loss or weight gain
  • Low sex drive
  • Constipation
  • Diarrhea

You might notice these symptoms before you have any psychological symptoms of depression, or you might notice them at the same time. Your doctor can help you figure out the source of your symptoms.

It can be scary to take that first step and ask your doctor for help. But you can make it easier by being prepared and setting yourself up for a successful appointment.

The most important thing is to be open and honest when talking about yourself and your depression symptoms during the initial and all following appointments. The more information your doctor has to work with, the better the chances of a proper depression diagnosis and effective treatment plan.

You can prepare for your appointment by writing down why you’re concerned about depression and specific symptoms of depression you might have. This takes the stress off having to remember everything during your visit. It’s also helpful to get an in-depth family history from relatives before meeting with your doctor if you can. Here are some suggestions of what you can take note of and bring to the doctor’s office:

  • Your mental and physical health concerns
  • Symptoms you've noticed
  • Unusual behaviors you've had
  • Past medical and psychological illnesses
  • If you have a family history of mental illnesses, including depression
  • Medications (both prescribed and over-the-counter) you’re taking now and in the past
  • Side effects of medications you currently take or have taken
  • Natural dietary supplements you’re taking
  • Your lifestyle habits (exercise, diet, smoking, alcohol consumption, drug use)
  • Your sleep habits
  • Causes of stress in your life (such as marriage, work, or social stressors)
  • Questions you have about depression and depression treatments, including medications

The biggest hurdle to diagnosing and treating depression is recognizing that someone has it. Unfortunately, about half of the people who have depression never get diagnosed or treated. And not getting treatment can be life-threatening: more than 10% of people who have depression take their own lives.

When depression is hurting your life, such as causing trouble with relationships, work issues, or family disputes, and there isn't a clear solution to these problems, you should seek help to keep things from getting worse, especially if these feelings last for any length of time.

If you or someone you know is having suicidal thoughts or feelings, call 911 or go to the emergency room right away.

Going to the doctor for a depression diagnosis can be scary, but with an accurate diagnosis, your doctor can offer you treatments that can help you feel better. Being prepared for your appointment and speaking openly and honestly about your symptoms will help your doctor understand what is happening. You may have to have a physical examination and tests to rule out other illnesses that could cause the same type of symptoms as depression.

What are the diagnostic criteria for depression?

The diagnostic criteria for depression are based on symptoms and how they affect your life. For example, for major depressive episodes, you would experience a depressed mood or loss of interest and pleasure in life for at least 2 weeks, plus four other symptoms, such as insomnia, fatigue, or feelings of worthlessness.

What are the three levels of depression?

If you have depression, it can be mild, moderate, or severe.

How do you write a depression diagnosis?

Doctors write a depression diagnosis outlining the type of depression the patient has, such as major depressive disorder, seasonal affective disorder, or bipolar disease.